There’s a few other solutions in addition to the two mentioned above that does not involve increasing the barrier to entry or reducing governance rewards.
One of these solutions (shown below) is detailed in this post
I disagree with both solutions advertised here as they either act to raise the barrier to entry for submitting proposals (form of censorship), or reduce the governance voting rewards (decrease incentive). Both lead us in the opposite direction of where we want to be going in terms of NNS participation.